PHYSIO BIO 2.2

Francis Galton

father of eugenics.

Eugenics

coined the term "eugenics" in 1883,

defining it as the science of improving human

populations by controlled breeding to increase

the occurrence of desirable heritable

characteristics.

Positive Eugenics

Encouraged the reproduction of people with perceived

desirable traits, such as intelligence, physical health, and moral character.

Negative Eugenics

Discouraged or prevented the reproduction of

people with perceived undesirable traits, such as mental illness,

physical disabilities, and criminal tendencies.

Genetic Inheritance

Genes are passed from parents to offspring, determining a wide

range of characteristics, from physical traits to behavioral tendencies.

DNA (Deoxyribonucleic Acid)

The molecule that carries genetic information in

all living organisms. It is composed of nucleotides arranged in a double helix structure.

Genes

Segments of DNA that code for

proteins, which carry out most of the

functions in a cell. Genes are the basic

units of heredity

Alleles

Different versions of a gene that

can lead to variations in a trait (e.g., blue

eyes vs. brown eyes). An individual inherits

two alleles for each gene, one from each

parent.

Complex Traits

Many traits, such as height, skin color, and intelligence, are

influenced by multiple genes

Gene-Environment Interactions

The expression of polygenic

traits can be influenced

by environmental factors,

such as nutrition, stress,

and education.

Meiosis

is a type of cell division that reduces the chromosome number by half, resulting in the formation of haploid gametes (sperm and eggs). Consists of two rounds

Reproduction

is the biological process by which new individuals are produced, involving the transmission of genetic material from parents to offspring. The process is key to the continuity of species and the inheritance of traits.

Prophase I

Chromosomes condense, homologous

chromosomes pair up, and crossing over occurs.

Metaphase I

Paired homologous chromosomes align at the

cell's equator.

Anaphase I

Homologous chromosomes are pulled to opposite

poles

Telophase I

Two haploid cells are formed, each with half the

number of chromosomes.

Meiosis II

Similar to mitosis, where sister chromatids are

separated, resulting in four genetically unique haploid cells.

Fertilization

union of a sperm cell and an egg cell to form a zygote, which

contains the full diploid number of chromosomes (46 in humans).

Zygote Formation

The zygote undergoes multiple rounds of cell division (mitosis) to develop into an embryo. The genetic material from both parents combines to create a unique genetic profile in the offspring.

Human Reproduction

In humans, the process of reproduction involves the

production of sperm in males (spermatogenesis) and eggs in females (oogenesis), followed by fertilization, implantation, and development of the fetus.

Genetic Disorders

Errors in meiosis or fertilization can lead to genetic disorders, such as Down syndrome (trisomy 21), where an individual has an extra chromosome.

Deletion

a segment of a chromosome that is missing or deleted, leading to the loss of genetic material.

Duplication

a segment of a chromosome that is duplicated, resulting in extra

genetic material.

Inversion

a chromosome segment that breaks off, flips around, and

reattaches, reversing the order of genes. Inversions can be paracentric (involving one arm) or pericentric (involving both arms, including the centromere).

Translocation

segment from one chromosome is transferred to another

chromosome. This can be reciprocal (exchange of segments between two chromosomes) or Robertsonian (fusion of two acrocentric chromosomes).

Aneuploidy

abnormal number of chromosomes due to nondisjunction during meiosis, resulting in cells with extra or missing chromosomes.

Karyotyping

laboratory technique that produces an image of an individual's chromosomes, allowing for the detection of large chromosomal abnormalities, such as aneuploidies and large deletions or duplications.

FISH (Fluorescence in Situ Hybridization)

a technique that uses fluorescent probes to bind to specific DNA sequences on chromosomes, allowing for the detection of small deletions, duplications, and translocatio

Comparative Genomic Hybridization (CGH)

A molecular technique that compares the DNA of a patient with a reference sample to identify gains and losses of DNA segments across the genome.

Down Syndrome (Trisomy 21)

An extra copy of chromosome 21. Intellectual disability,

characteristic facial features (such as a flat facial profile, upward

slanting eyes, and a small nose), heart defects, and an increased

risk of certain medical conditions like leukemia and Alzheimer’s

disease.

Turner Syndrome (Monosomy X)

Females have only one X chromosome (45, X). Short stature,

webbed neck, broad chest, underdeveloped secondary sexual

characteristics, and infertility. Some individuals may have heart

defects or learning difficulties, particularly with spatial rea soning

Klinefelter Syndrome (XXY)

Males have an extra X chromosome (47, XXY). Tall stature, reduced muscle mass, body hair, and testosterone levels, infertility, and learning disabilities, particularly with language and reading. Individuals may also have a higher risk of developing certain health issues, such as osteoporosis and breast cancer.

Patau Syndrome (Trisomy 13)

An extra copy of chromosome 13. Severe intellectual disability,

congenital heart defects, brain abnormalities,cleft lip/palate, polydactyly (extra fingers or toes), and severe developmental delays. Most affected infants do not survive past the first year of

life.

Edwards Syndrome (Trisomy 18)

An extra copy of chromosome 18. Severe intellectual

disability, low birth weight, small head (microcephaly), clenched fists with overlapping fingers, heart defects, and severe developmental delays. Like Patau syndrome, many affected

individuals do not survive beyond infancy.